<i>In-Situ</i>Monitoring of Chemical Vapor Deposition from Trichlorosilane Gas and Monomethylsilane Gas Using Langasite Crystal Microbalance

Using the langasite crystal microbalance (LCM), the trends in film thickness produced by means of the chemical vapor deposition using trichlorosilane gas, monomethylsilane gas and their mixed gas were observed at 600?C and evaluated by comparison with the information from a transmission electron microscope (TEM). The crystalline silicon film thickness from trichlorosilane gas was comparable to that of an amorphous silicon carbide film from monomethylsilane gas. The film obtained from the gas mixture was amorphous and was the thinnest in this study. Because the thickness trend obtained by the LCM agreed with that by the TEM, the LCM is shown to be a convenient evaluation tool for the behavior of various film deposition.

Room Temperature and Reduced Pressure Chemical Vapor Deposition of Silicon Carbide on Various Materials Surface

At room temperature, 300 K, silicon carbide film was formed using monomethylsilane gas on the reactive surface prepared using argon plasma. Entire process was performed at reduced pressure of 10 Pa in the argon plasma etcher, without a substrate transfer operation. By this process, the several-nanometer-thick amorphous thin film containing silicon-carbon bonds was obtained on various substrates, such as semiconductor silicon, aluminum and stainless steel. It is concluded that the room temperature silicon carbide thin film formation is possible even at significantly low pressure, when the substrate surface is reactive.

Molecular Adsorption and Desorption Behavior on Silicon Surface in a Complex Ambient Atmosphere Containing Vapors of Diethylphthalate, Acetic Acid and Water

Using a complex ambient atmosphere containing vapors of an organic compound, acid and water, the molecular adsorption and desorption behavior on a silicon surface was studied using the in-situ measurement of a quartz crystal microbalance linked to the rate theory. Because the behavior of diethylphthalate (DEP) could be reproduced assuming a single-component system, acetic acid (ACA) and DEP are concluded to separately exist in the water film and at the water film surface, respectively. This conclusion was obtained from both the adsorption and desorption behaviors. The process developed in this study is useful for determining the layer in which chemical compounds are present.

Improvement in potassium ion batteries electrodes: Recent developments and efficient approaches

Demand for efficient and continuous application for high-grid energy storage systems involves the study towards novel battery technologies. Hence, considering the vast naturally available resources of potassium all over the world and its encouraging intercalation chemistries, it has recently enticed attention in electrochemical energy storage industry in the form of potassium ion batteries (PIBs). The major factor in this K+ based battery, is to develop efficient approaches to manufacture electrode substance to intercalate its big size potassium ions with considerable voltage, kinetics, charge/discharge capacity, capacity retention, cost, etc. This study contributes in the recent developments of anode and cathode materials for PIBs, including several electrode materials in regards to synthesis, structure, electrochemical performance, and K-storage mechanisms. Finally, the review contributes to provide helpful sources for the increasing number of scientists working in this industry regarding its critical issues and challenges and also to indicate the future direction of electrode materials in PIBs.

Experimental investigation of the influence of carbonated water on sandstone and carbonate rock properties

Laboratory measurements using nuclear magnetic resonance,scanning electron microscopy,and gas porosity and permeability analysis were conducted to acquire a petrophysical interpretation of the Carbon Tan Sandstone and Savonnieres Carbonate for potential carbon dioxide storage in subsurface formations.The relationships between pore structures,such as pore-size distribution,pore geometry,and porosity/permeability,were investigated near and far from the wellbore.At operating pressures of 2500psi(17.24 MPa)and temperatures of 176F(50℃),carbonated water was injected into a composite core constructed of two similar core samples bounded by a compact disc located between them.The current results showed that a strong calcite dissolution took place near the injection position of both rock samples and led to improvements in the primary intergranular permeability and porosity,while the carbonate sample showed significant improvement compared to sandstone.The durable heterogeneous dissolution of calcite grains also led to the creation of new pores as intra-granular micro-pores.While at deeper depths from the injection position,it noticed an insignificant development in pore structure and its populations as well as rock hydraulic properties of both rock samples.In conclusion,the study revealed that the injected carbonated brine had a valuable impact on fluid-formation interactive,which improved rock's inlet properties compared with outlet.

A review on co-pyrolysis of agriculture biomass and disposable medical face mask waste for green fuel production:recent advances and thermo-kinetic models

The Association of Southeast Asian Nations is blessed with agricultural resources,and with the growing population,it will continue to prosper,which follows the abundance of agricultural biomass.Lignocellulosic biomass attracted researchers’interest in extracting bio-oil from these wastes.However,the resulting bio-oil has low heating values and undesirable physical properties.Hence,co-pyrolysis with plastic or polymer wastes is adopted to improve the yield and quality of the bio-oil.Furthermore,with the spread of the novel coronavirus,the surge of single-use plastic waste such as disposable medical face mask,can potentially set back the previous plastic waste reduction measures.Therefore,studies of existing technologies and techniques are referred in exploring the potential of disposable medical face mask waste as a candidate for co-pyrolysis with biomass.Process parameters,utilisation of catalysts and technologies are key factors in improving and optimising the process to achieve commercial standard of liquid fuel.Catalytic copyrolysis involves a series of complex mechanisms,which cannot be explained using simple iso-conversional models.Hence,advanced conversional models are introduced,followed by the evolutionary models and predictive models,which can solve the non-linear catalytic copyrolysis reaction kinetics.The outlook and challenges for the topic are discussed in detail.

Utilization of microwave steam pyrolysis to produce biochar for thermal energy storage

Microwave steam pyrolysis(MSP)is an innovative thermochemical approach to converting biomass into high-quality biochar using steam to improve the dielectric heating of microwave radiation.Biochar shows high fixed carbon and carbon contents at a maximum temperature of 550℃in 10 min.The MSP achieved a heating rate of 112℃/min from 200℃to 400℃to produce biochar effectively.Furthermore,the thermal properties of biochar in microwave heating were investigated in this study to explore its potential as a microwave heat-absorbent material.Microwave is able to perform volumetric and controllable heating to the biochar.Moreover,biochar shows good microwave heat absorbency,storing and transferring heat effectively.The temperature profile of three different sizes of biochar was investigated to examine the efficiency of biochar in heat absorption from microwave radiation.It was found that the powder form of biochar showed a higher heat transfer rate of 40℃/min and a low cooling rate of 7.5℃/min.The presented results are useful for evaluating the application of biochar as a promising medium for heat storage systems.

Metal Fluorides Produced Using Chlorine Trifluoride Gas

For developing coating materials, the fluorides of scandium, lanthanum, strontium, barium, magnesium and aluminum were produced from their oxides and chlorides by means of exposure to chlorine trifluoride gas at temperatures between room temperature and 700°C. The metal chlorides could be easily fluorinated even at room temperature, while the metal oxides required temperatures higher than 300?C. After the heating in ambient hydrogen at 1100°C, the fluorides of lanthanum and barium showed very low weight losses at 1100°C, although the weights of the other fluorides significantly decreased. These materials may work as protective films against corrosive and high temperature environments, particularly when using the chlorine trifluoride gas.

Bio-oil production from pyrolysis of oil palm biomass and the upgrading technologies:A review

Oil palm biomass(OPB)represents major portion of the lignocellulosic waste in Malaysia that can be converted into bio-oil.This review aims to provide important insights in OPB-derived bio-oil production by first discussing the chemical compositions of different OPB and their effects to the bio-oil yield and quality obtained from pyrolysis process,followed by discussing the addition of plastics and catalysts into the pyrolysis for bio-oil upgrading,and lastly summarizing the existing technoeconomic and environmental studies and the potential use of process integration and intensification in this topic.Polypropene(PP),low density polyethylene(LDPE),and high density polyethylene(HDPE)have been commonly used in co-pyrolysis of OPB,which can effectively increase the heating value of bio-oil up to 80%that of diesel.Likewise,acidic,basic,and neutral catalysts have been applied to increase the amount of hydrocarbon and phenol in the bio-oil,further improving the heating value to be comparable to diesel.The bio-oil production from OPB is currently still limited to demonstration scale despite the favorable environmental compatibility and technoeconomic feasibility shown by studies focused on empty fruit bunch(EFB).Several promising advanced pyrolysis processes that integrate other processes such as anaerobic digestion,hydrogen production process,and heat and power generation units as well as the advanced reactor designs are also overviewed here as future innovation of the bio-oil production from OPB,which may play more significant role as the technology matures.

Slim Water Injection Nozzle for Silicon Wafer Wet Cleaning Bath

In order to effectively and quickly clean the surface of semiconductor silicon wafers, the fluid flow is one of the significant issues. For a batch-type silicon wafer wet cleaning bath, a slim water injection nozzle consisting of a dual tube was studied, based on theoretical calculations and experiments. A thin inner tube was placed at the optimum position in the water injection nozzle. Such a simple design could make the water injection direction normal and the water velocity profile symmetrical along the nozzle. The water flow in the wet cleaning bath was observed using a blue-colored ink tracer. When the nozzle developed in this study was placed at the bottom of the bath, a fast and symmetrical upward water stream was formed between and around the wafers.

Improving cold flow properties of palm fatty acid distillate biodiesel through vacuum distillation

Palm fatty acid distillate(PFAD),a by-product of refining process of crude palm oil can be used as a potential feedstock for biodiesel production.However,the application of palm oil-based biodiesel is often hinder by its poor cold flow properties(CFP).Biodiesel fuel with poor CFP may crystallize and result in clogging of fuel lines,filters and injectors that cause engine operability problems.For that,a vacuum distillation method was designed and its feasibility and efficiency in improving the CFP was examined.A total of 13.60wt%of total saturated fatty acid methyl esters were successfully removed from the PFAD biodiesel,resulting in the improvement of the cloud point(CP),cold filter plugging point(CFPP)and pour point(PP)of PFAD biodiesel from 20℃,19℃,and 15℃to 13℃,11℃,and 9℃,respectively.It is remarkable that the improved CFPP satisfied the requirements for grade C summer biodiesel for temperate climates in EN 14212 standard.Additionally,Sarin(U FAME)empirical correlation was evaluated and it was found to have a good prediction of CFP for PFAD biodiesel,with lower than 2℃deviation.